Field of the Invention The invention relates to a configuration of a steam generator, in particular of a low temperature carbonization-combustion plant, including a multi-segment flue gas channel being disposed in a supporting structure and having a first vertical segment connected through a second at least approximately horizontal segment to a third likewise vertical segment, so that the flue gas channel forms a structural unit and the first segment is suspended in the supporting structure by means of supporting members.
With such a steam generator that is known from U.S. Pat. No. 3,001,514, hot flue gases produced in a combustion chamber flow through a flue gas channel which essentially is formed of three segments. The walls of the flue gas channel are equipped with heating surfaces in the form of tubes or tube bundles which are integrated into a water-steam loop. The combustion chamber represents a first vertical segment of the flue gas channel. The combustion chamber is connected through a second, horizontal segment of the flue gas channel to a third segment, which is likewise vertical and opens into a waste heat boiler for steam generation. The water flowing through the heating surfaces serves to cool the combustion chamber and the waste heat boiler, and is at least partly vaporized by means of indirect heat exchange with the hot flue gas. The combustion chamber is fueled with low temperature carbonization gas from a low temperature carbonization plant, for example. A low temperature carbonization-combustion plant is known from European Patent No. 0 302 310, for example.
In order to compensate for restrictions to expansion and deformations of the spatial configuration of the steam generator due to vertical and horizontal thermal expansion, the segments of the flue gas channel, i.e., the heating surfaces of the combustion chamber and the waste heat boiler, are normally structurally separate from one another. Cooling of the combustion chamber takes place by means of forced circulation while the waste heat boiler is cooled by means of natural circulation.
Heretofore, thermal expansion was prevented by structurally separating the heating surfaces of the combustion chamber and those of the waste heat boiler. Cooling of the combustion chamber was carried out by means of forced circulation while the waste heat boiler was cooled by means of natural circulation.